T.C.
My son was 2 when he went through this also. He would only hit me. It lasted for a while, but i would just grab is hand tell him NO, and then take my hand and touch his face and say gently. We be gentle and then have him do that to me so he learned what being gentle was. If he continued to hit he would sit in a time out. I agree, you need to just keep putting him there. My son is almost 3 now and i still have to bring him back a few times before he will sit there. Good luck, i know it is frustrating but the stage will pass.